Enhanced plasma oxidation at low temperature using a thin solid electrolyte film

Low-temperature anodic oxidation in a ’’cold’’ plasma (multipole) of metals like Al or Ta through a thin calcia-stabilized zirconia (CSZ) film is possible. Thick (≳300 nm) stoichiometric metal oxides are formed under the CSZ with high growth rates (20–30 nm/min). Anodization of bare metals under similar plasma conditions leads to very low oxidation rates (<1 nm/min). The CSZ film, which acts as a selective oxygen filter, has thus greatly enchanced the oxidation rate. Low-temperature (<50 °C) plasma anodization of silicon (typical rates 2–3 nm/min) is also possible through a thin CSZ film.